Ineta Dzinguviene was sentenced in 2011 to 15 years after smothering son Paulius in Fraserburgh in April 2010 just hours after birth.
Now she has been sentenced to another 15 years for murdering newborn Paulina at her old family home in Marijampole, Lithuania, in 2009.
Kaunas Regional Court confirmed that Dzinguviene, who was extradited back to Lithuania last year, pled guilty to the crime during a prolonged private hearing.
She admitted smothering Paulina with a polythene bag. Dzinguviene will serve her sentence in Lithuania.
Dzinguviene, the wife of a migrant Lithuanian who drove a van for a fish factory, moved with her husband and her other three children to Fraserburgh in February 2010. She hid her pregnancy from friends and refused to attend antenatal classes.
After she killed the baby his body was dumped in a holdall in a communal hallway.